This invention relates to an improvement of a device adapted to control an elevator.
The armature of an electric motor for driving an elevator, a traction sheave, a secondary sheave and a tension sheave are rotary elements which are precisely machined. However, they are still somewhat eccentric, and unbalanced in terms of moments. The armature may, for example, produce torque ripples. Therefore, if the frequency of the force of vibration generated by these rotary elements coincides with the inherent frequency of the main rope or the compensation rope of the elevator, individuals in the cage can feel the vibration. That is, they sense the vibrations and can be uncomfortable given the environment of an elevator.
Especially in the case of an elevator extending over long distances, the vibration is liable to be caused in the cage because the inherent frequency of the main rope or the compensation rope is low. In such an elevator, the vibration of the main rope is amplified ten to twenty times, and therefore the slight force of vibration produced by the rotary elements greatly affects the vibration values in the cage.